Freeing the environment of toxic chemicals and compounds is an increasing concern of all. Unfortunately however, their presence usually is unknown until they reach dangerous levels. After hazardous concentrations have been built up, an area may be considered life-threatening and barred from access or an expensive cleanup must be undertaken. These courses of action are extreme and could be avoided by early detection and appropriate action.
Pollution of seawater is harder to isolate and remedy, so early detection is more urgent. One family of toxic pollutants of seawater is generally referred to as organotin compounds. This family of alkyl tin compounds is widely used as stabilizers for plastics, especially rigid vinyl polymers used as piping, construction aids and cellular structures. They are both liquids and solids and all are highly toxic with a tolerance of 0.1 milligrams per cubic centimeter of air. Typcial objectionable organotin compounds are butyl tin trichloride, dibutyltin oxide, etc. and various methyltin compounds.
Heretofore, arriving at reliable figures for determination of organotin compound concentrations has been hampered due to the lack of a suitable device for trapping the compounds and making an analysis or detection of their presence and concentration. This has been particularly true in the case of seawater analysis where some of the organotin compounds have been leached into seawater from various anti-fouling coatings.
One current trapping method of the organotins involves manually immersing a "V" shaped pyrex tube trap into a container of liquid nitrogen for a given time. A gas sample of a particular gas is bubbled through a seawater sample to pick up the organotins of interest and is fed through the V shaped tube. After a predetermined time, the tube is lifted out of the liquid nitrogen and allowed to come up to an ambient temperature. As the gas sample makes the transition to the ambient temperature several of the compounds of interest are eluted and fed to a detector-analyzer. Next the tube is manually transferred to a hot silicon oil bath (at about 150.degree. C.) to elute the remaining compounds and any water vapor that might be trapped in the tube. Obviously this procedure does not lend itself well to automation since it requires a number of manual operations. These manual operations are not exact and introduce the problems normally associated with doubtful reliability. As a further consideration, manually immersing the tube in the hot oil bath poses a hazard to technicians and operators.
Thus a continuing need exists in the state-of-the-art for an organotin trap that provides a stable, controllable and repeatable trapping and eluting of organotin compounds of interest while not posing a safety hazard for operating personnel.